1. Field of the Invention
The present invention relates to a foot-operated parking brake device for vehicles such as motor car and in particular, relates to a foot-operated parking brake device for vehicles which is capable of releasing the locking of a parking brake by doing the same manipulation as done for locking the parking brake.
2. Discussion of the Related Art
As foot-operated parking brake devices for vehicles of this kind, there has been known one which is described in Japanese unexamined, published patent application No. 2004-182135. The known device is composed of a pedal arm 20 which is attached at its one end to a mounting bracket 11 secured to a vehicle body, to be pivotably within a vertical plane and which has a parking brake control cable 40 connected to the side of said one end and a pedal pad attached to the other end thereof, and a rock mechanism 30 which operates to lock the pedal arm 20 when the same is stepped on and to release the locking when the pedal arm 20 is stepped on again. The same reference numerals as used in the aforementioned Japanese application are used in this section hereof.
The lock mechanism 30 is composed of plural ratchet teeth 31a which are provided on the mounting bracket 11 to align along an arc having a center coaxial with the pivot axis of a pedal arm 20, a pole 32 attached to the pedal arm 20 to be pivotably and slidable and having an engaging claw (ratchet claw) 32d disengage ably engaged with the ratchet teeth 31a, a release lever 33 attached to the pedal arm 20 to be pivotably in approximately coaxial alignment with the pole 32, a spring 34 for urging the pole 32 and the release lever 33 to pivot in opposite directions with each other, a pole pivot limiting portion (right side wall) 22b and a release lever pivot limiting portion (left side wall) 22a for respectively limiting pivot movements of the pole 32 and the release lever 33, and a pole abutting portion (engaging protrusion) 32e and a release lever abutting portion (engaging protrusion) 33e formed on the pole 32 and the release lever 33 for respectively limiting pivot movements of the pole 32 and the release lever 33 upon abutting on each other.
Before the pedal arm 20 is locked, the lock mechanism 30 as constructed above is in a first state (refer to FIG. 3) that the pole 32 and the release lever 33 are kept in abutting on each other not to pivot relatively as a result being pivoted by the urging force of the spring 34 being in the first position in pivot directions which make the pole abutting portion 32e and the release lever abutting portion 33a come close to each other and that the engaging claw 32d of the pole 32 is engage able with the ratchet teeth 31a. After the stepping force on the pedal arm 20 is released subsequently of the locking operation, the lock mechanism 30 is in a second state (refer to FIG. 6) that the pole 32 and the release lever 33 are kept in abutting respectively on the pole pivot limiting portion 22b and the release lever pivot limiting portion 22a not to pivot relatively as a result of being pivoted by the urging force of the spring 34 being in the second position in pivot directions which make the pole abutting portion 32e and the release lever abutting portion 33a go away from each other and that the engaging claw 32d of the pole 32 is kept released from the state in which the engaging claw 32d of the pole 32 is engage able with the ratchet teeth 31a. 
When the driver steps on the pedal pad 25 again to release the locking of the pedal arm 20, the pedal arm 20 is slightly pivoted counterclockwise from the state shown in FIG. 5. As a result, the engaging claw 32d is disengaged from the ratchet teeth 31a, and the pole 32 is pivoted counterclockwise by the urging force of the spring 34 to be stopped upon abutting on the right side wall 22b (refer to FIG. 6). Then, as the driver relaxes the stepping force being exerted on the pedal pad 25, the pedal arm 20 is pivoted by the urging force of a return spring to return from an operating position toward an original position (the state shown in FIG. 1) being an inoperative position. In the beginning of the return motion, since the lock mechanism 30 is in the second state, the pole 32 and the release lever 33 have been pivoted by the urging force of the spring 34 respectively counterclockwise and clockwise. When the abutting protrusion 33b of the release lever 33 comes into abutting on the abutting portion 14 of the mounting bracket 11, the release lever 33 is pivoted counterclockwise against the urging force of the spring 34. When the further pivot movement of the pedal arm 20 causes the release lever 33 to pivot further, the spring 34 is turned over to the first position to return the lock mechanism 30 to the first state (refer to FIG. 3).
In the foregoing foot-operated parking brake device for vehicles, the spring 34 is also returned from the second position to the first position when the lock mechanism 30 is returned from the second state to the first state to release the pedal arm 20 being locked. Before this returning, the pole 32 and the release lever 33 remaining in the second state have been pivoted by the urging force of the spring 34 in the second position respectively counterclockwise and clockwise, and the pole abutting portion 32e and the release lever abutting portion 33a have been separated from each other with the space therebetween. However, with the returning of the spring 34 to the first position, the pole 32 and the release lever 33 are pivoted by the urging force of the spring 34 being in the first position respectively clockwise and counterclockwise, whereby the pole abutting portion 32e and the release lever abutting portion 33a having been separated so far come close with great force. This gives rise to a problem that a large collision noise is generated at the moment of such collision.